1. Field of the Invention
The present invention relates to an up-and-down turntable for use in a microwave oven, and more particularly, a turntable which enables to be moved up and down during its rotation for uniformly heating the cooking object.
2. Description of the Prior Art
In a conventional art, a microwave oven as shown in FIG. 1 contains a turntable which, during its rotation, is moved up and down to heat the cooking object although the heat cannot heat the cooking object uniformly.
The conventional turntable 1' as shown in FIG. 1 is operatively disposed in an annular holder 11' of a bottom plate 10'. An annular cam member 6' disposed in a case 3' includes a gear 8' disposed thereon and an inclined cam face 6". The case 3' is provided with a motor 2' of which a shaft 2a is coaxially mounted with a super gear 9' which gears together with the gear 8' of the cam member 6' which is adapted to receive an axle 7' disposed therein.
According to the prior art (FIG. 1) the turntable is driven for rotation by the super gear 9' which is mounted coaxially with the shaft 2a' of the motor 2'. And the rotation of the super gear 9' is caused to rotate the cam member 6' by gearing together with the gear 8' and also to rotate the turntable which is operatively connected to the cam member 6'.
The inclined cam face 6" disposed on the bottom surface of the cam member 6' operatively contacts with a roller 12', therefore, the rotating turntable 1' is moved up and down the distance between the dotted line position and the solid line position as shown in FIG. 1.
However, the conventional turntable is required many components since the mechanism of the up-and-down movement of the turntable in rotation becomes complicated. Furthermore, since the cam face 6" has a fixed, inclined configuration, the cam face limits the up-and-down movement of the turntable. Therefore, the microwave applies only in a limited portion of the cooking object.